The instant invention does not have any exposed parts. Road salt, dirt and rocks may not enter the solenoid valve of the instant invention which is substantially encapsulated with a glass-filled nylon housing. A glass-filled nylon body is ultrasonically welded to the housing. The nylon housing seals against the body, bobbin, stop, coil and straps. Thus, a completely sealed solenoid valve is provided. The housing in combination with the body completely seals the solenoid valve from dirt and other contaminants.
Other solenoid valves for use in automatic brake systems are known such as U.S. Pat. No. 5,123,718 to Tyler and U.S. Pat. No. 5,234,265 to Tyler. Neither of these patents teach encapsulation of the solenoid valve with a nylon housing so as to prevent road salt, dirt and rocks from entering the valves. These related art solenoid valves employ an armature movable within a core.
U.S. Pat. No. 5,710,535 to Goloff discloses an encapsulated coil, bobbin and insert. The insert in Goloff prevents contaminants from entering the coil assembly along the electrical leads.
Other related art devices such as U.S. Pat. No. 4,604,600 to Clark, U.S. Pat. No. RE 32,873 to Clark, and U.S. Pat. No. 3,633,139 to Thompson employ armature guide tubes. The instant invention does not employ guide tubes. The armature, or plunger of the instant invention, is guided by the bobbin.
The related art does not teach or suggest a body affixed to a housing molded over the coil and bobbin. Nor does the related art teach or suggest an overmolded housing which restrains the stop and is ultrasonically welded to the body.
A solenoid valve partially encapsulated by glass filled nylon is disclosed. Preferably, the encapsulant is a 33% glass-filled nylon sold under the trademark ZYTEL which is believed to be a trademark of Dupont Corporation. Other materials may be used for the encapsulant. Two embodiments are disclosed.
In the first embodiment, a body having a first port is disclosed. A plunger is employed which includes a sealing insert which either blocks or permits flow through a stop. The sealing insert is operated against a bore in a stop. The insert is rubber and it is bonded to stainless steel. The stop includes a crowned surface which facilitates sealing by the insert.
In the second embodiment, a body having a first port and second port is disclosed. A plunger is employed which includes an insert operable against one of the ports in the body.
The two embodiments are similar but have notable differences. First, the bodies are different in each embodiment. Second, the plunger orientation in the second embodiment is reversed. A stop having a crowned surface is used in the first embodiment and a stop having a flat surface is used in the second embodiment.
In the first embodiment the insert is operable against the crowned surface of the stop and in the second embodiment the insert is operable against the body. The plunger of the invention includes two longitudinal channels which run down the side of an otherwise cylindrical plunger. One end of the plunger includes a bore and a groove communicating with the bore. The plunger is made of stainless steel and includes a rubber insert which is 0.093 to 0.099 inches thick. The plunger is primarily guided by the bobbin.
A stop is utilized in the invention and includes a bore therethrough. A spring resides between the stop and the plunger urging the plunger away from the stop and toward the body. The stops, in both embodiments, are restrained by the housing.
Glass-filled nylon is molded over: the bobbin; the coil wound around the bobbin; and, the straps. The straps and the nylon housing restrain the stop and secure it in place. The glass-filled nylon body is ultrasonically welded to the glass-filled nylon housing.
It is an object of the present invention to provide a solenoid valve which does not admit rocks, salt, water or other debris thereto.
It is a further object of the present invention to provide a solenoid valve which includes a glass-filled nylon housing.
It is a further object of the present invention to provide a solenoid valve which does not include a guide tube.
It is a further object of the present invention to provide a solenoid valve which includes rubber bonded to a stainless steel plunger for sealing against an orifice.
It is a further object of the present invention to provide a solenoid valve which includes a plunger having longitudinal channels and a bore communicating with a groove at one end thereof.
It is a further object of the present invention to provide a normally open solenoid valve which includes a plunger oriented such that it is operable between first (open, deenergized) and second (closed, energized) positions against a stop.
It is a further object of the present invention to provide a normally closed solenoid valve which includes a plunger oriented such that it is operable between first (closed, deenergized) and second (open, energized) positions against an orifice in a body.
It is a further object of the present invention to provide a solenoid valve which includes a stop having a bore.
It is a further object of the present invention to provide a solenoid valve having a body ultrasonically welded to a housing.
It is a further object of the present invention to provide a solenoid valve which employs the bobbin to guide the plunger.
It is a further object of the present invention to provide a stop having a crowned surface and a bore therethrough. The crowned surface is operable against a rubber insert.